Flow deformation presses



July 7, 1964 K. GRIESINGER 3,139,984

mow DEFORMATION PRESSES Filed April 28, 1961 ATTORNEY j United States Patent 3,139,984 FLOW DEFORMATION PRESSES Karl Griesinger, Jebenhausen, Wurttemberg, Germany,

assignor to L. Schuler AG, Goppingen, Wurttemberg, Germany Filed Apr. 28, 1961, Ser. No. 106,386 Claims priority, application Germany May 4, 1960 3 Claims. (Cl. 2079) The invention relates to a flow deformation press. It has already been proposed by the applicant to provide either twice as many punches as dies or conversely twice as many dies as punches in. order to gain the advantage of lengthening the time available either for stripping the pressing from the punch or for feeding the blank into the die, in such manner that substantially more time will thus be available than when using only one punch or one die at the same rate of reciprocation.

The duplicated punches or dies may be located, for instance, on a drum which is indexed to move a fresh punch or die into working position for each consecutive operation. However, it is a matter of considerable difficulty to achieve the precision and accuracy which is essential to the satisfactory Working of such a press.

During the time which is available between two work,

ing strokes of the ram the respective tool must be replaced and a fresh tool moved within an accuracy of a few hundredths of a millimetre into the same position as the tool which has been replaced. Furthermore, the exchange must be performed with the same high precision at the end of each reciprocation.

These high demands on operational accuracy will be readily understood when it is remembered that the punch must necessarily always align exactly centrally with the axis of the cavity of the die. Since the flowdeformed pressing may have a wall thickness of not more than a few tenths of a millimetre, an eccentricity of the punch amounting to say two hundredths of a millimetre will cause the thickness of the wall of the pressing to exhibit considerable differences. In the assumed case one side of the pressing would have a wall which is only 0.08 mm. thick, whereas the wall on the other side would be 0.12 mm. These differences in wall thickness may have very undesirable consequences during the further processing of the pressing and they may mean that the pressing must be discarded as waste.

Alternatively, the duplicated tool may be mounted on a disc indexed to move one tool into working position by each indexing motion. Nevertheless, it is still extremely difficult in such an arrangement to ensure that the indexing of the disc is sufficiently precise.

The invention solves this problem by using a reciprocatory motion for alternately moving the relative tools into working position in such a way that the end of the movement into working position is determined by adjustable limit stops and that in working position the tool carrier is maintained in contact with the limit stop by spring means.

The special advantage secured by this invention is that it uses a relatively simple device which can be provided with a minimum of structural means for achieving that degree of precision in the alternating motion transversely across the direction of the stroke of the press which is essential to the satisfactory operation of the machine. The employment of a reciprocatory movement for changing the relative tool affords the advantage that nonmoving limit stops can be used, a possibility which is not readily available when relying on the unidirectional indexing motion of say a drum.

However, the possibility of using fixed limit stops is not in itself sufficient for achieving the wanted high accuracy. This cannot be achieved unless these latter fea- 3,139,984 Patented July 7, 1964 ice tures are combined with the third above mentioned feature, namely that which consists in maintaining the carrier of the relative tool which is moved into working position in contact with the limit stop by the pressure of spring means. This latter feature eliminates the eifect of unavoidable backlash in the drive means, which would otherwise be of significance in establishing the extremely high accuracies needed for securing fully satisfactory results.

In one embodiment of the invention in which one of the cooperating tools, for instance the punch, is duplicated and mounted on a common tool carrier which may be either slidably or pivotally reciprocable, the spring means may be constituted by a single spring acting on the tool carrier and located to pull or push the tool carrier against the respective limit stop in each end position, so that the resistance of said spring must first be overcome when the tool carrier is retracted from the stop until the carrier reaches a dead centre position in relation to the spring. In this embodiment of the invention the tool carrier is urged into contact with its limit stops independently of its drive means.

In another embodiment of the invention a spring element is incorporated directly in the transmission train for the motion across the direction of the stroke of the press. This embodiment of the invention has the advantage that the tool carrier does not strike the limit stops under the influence of the spring. The drive means in this embodiment are designed to urge the member which is movable across the direction of the stroke of the press beyond its limit stop, and thereby to energize the spring which then presses the tool carrier against the limit stop.

The adjustable limit stops may be constructed in various ways. In a particularly advantageous form of construction the stops are embodied in adjustable wedges which can be set as required by screw means. The face of the adjustable wedges which makes contact with the cooperating face of the tool carrier may be provided with a segment with a flat face cooperating with the corresponding face of the tool carrier, whereas the reverse side of this segment is circularly curved and swivels in a conformably shaped curved dished face of the wedge. This arrangement permits the motion-limiting face to adjust itself into accurate parallelism with the cooperating face of the tool carrier. In the case of a tool carrier which reciprocably swivels on a fulcrum this is a matter of considerable importance because full contact between the cooperating faces is thus always assured irrespectively of the amplitude of the angle of reciprocation.

Other features of the invention will be explained in course of the following description of an embodiment of the invention shown in the drawings and they will form the subject matter of claims. The several features of the invention may be used separately or in combination in any particular embodiment of the invention.

The accompanying drawing illustrates by way of example one form of construction of the invention, in which:

FIG. 1 is a longitudinal section taken on the line II in FIG. 2 of an embodiment of the invention showing those elements which are necessary for conveying an understanding of the invention; and

FIG. 2 is a section taken on the line IIII in FIG. 1.

In the embodiment of the invention shown in the drawings a ram 2 which carries a die 3 is slidably mounted in a frame 1 of a press. Guided on a press table an approximately V-shaped punch carrier 5 is arranged to swivel on a fulcrum 6 across the direction of reciprocation of the ram. Two punches 8 and 8 are affixed by interposed supporting members 7 to this punch carrier 5. The reciprocatory swinging motion is transmitted to the punch carrier 5 through a torsionbar 9 reciprocated by a crank 10, a crankpin 11 sliding in a cam slot 12 of a barrel 13 driven by a mainshaft 14 through a pinion 15 at a speed which is half that of the speed of the crankshaft which drives the ram 2.

Located on each side of the punch carrier 5 are wedges 16 which limit the angular reciprocatory motion of the punch carrier '5 in positions in which one of the punches 8 or 8' is exactly in working position. The wedges 16 are adjustable by screws 17 working in nuts 18 which can be set by means of a box spanner.

On the sides facing the punch carrier 5 the adjustable are fitted with segments-19 with fiat faces 20 and circularly curved backs 21 which are adapted to swivel in conformably circularly dished sockets 22 in the wedges 16. The faces 20 of the wedge members 16 which form the limit stops can thus swing into exact parallelism with the cooperating faces of the punch carrier when the latter makes contact with the wedges in its end positions.

The earn slot 12 is designed to move the crank into a position which would deflect the punch carrier 5 beyond the limits determined by the stop members In other words, the crank 10 continues to be deflected through a given distance after the punch carrier 5 has already made contact With one 'of the limit stops 16. This additional deflection causes the torsion bar 9 to be torsionally energized so that the punch carrier 5 will now be maintained in contact with the limit stop 16 by the tension of the energized torsion bar 9.

The inclusion of the torsion bar 9 in the train of driving elements has the further advantage of permitting a cam slot of simple shape to be used for reciprocating the punch carrier. This would not be possible if the cam means were required to satisfy high demands with respect to the precision of the motions which it controls. It is a matter of great difficulty to construct a cam drive in such a way that a high precision motion can be derived therefrom.

What I claim is:

1. A tool carrier for a flow-deformation press, comprising in combination, a carrier member pivotable between two working positions about an axis substantially perpendicular to the plane of said member, the latter being adapted to 'hold a pair of interchangeable press tools at locations radially spaced apart from said axis, said tools alternately facing another press tool in one of said working positions, adjustable limit stops located at both ends of the pivotal movement, and means for pivoting said carrier member so as alternately'to bring each of said tools opposite said another tool while the other tool is pivoted away therefrom, said pivoting means including a positively actuated crank member performing an angular movement larger than said pivotal movement of the carrier member, and a torsion bar connecting said members substantially along said axis, said torsion bar being adapted for urging alternate engaging surfaces of said carrier member into, and maintaining them in, contact with respective ones of said limit stops.

2. A tool carrier for a flow-deformation press, comprising, in combination, a carrier member pivotable between twoworking positionsabout an axis substantially perpendicular to the plane of said member, the latter being adapted to hold a pair of interchangeable press tools at locations radially spacedapart from said axis, said tools alternately facing another press tool in one of said working positions, adjustable limit stops located at both ends of the pivotal movement and including each a segmental member having a curved edge slidable along a corresponding portion of said limit stop and a fiat surface on the side opposite said curved edge, and means for pivoting said carrier member so as alternately to bring each of said tools opposite said another 1 tool while the other tool is pivoted away therefrom, said pivoting means including a positively actuated crank member performing an angular movement larger than said pivotal movement of the carrier member, and a torsion bar connecting said members substantially along said axis, said torsion bar being adapted for urging alternate engaging surfaces of said carrier member into, and maintaining them in, contact with respective ones of said limit stops, said fiat surfaces of the limit stops facing respective ones of said engaging surfaces, contact being maintained between said surfaces in said working positions by the intermediary of said torsion bar.

3. A tool carrier according to claim 2, further comprising adjusting means adapted to move said segmental members with respect to said engaging surfaces of the carrier member, whereby to regulate the moment at which said torsion bar becomes effective at said ends of the pivotal movement.

References Cited in the file of this patent UNITED STATES PATENTS 1,286,726 Noble Dec. 3, 1918 1,317,238 Summey Sept. 30, 1919 2,633,777 Hoern Apr. 7, 1953 2,671,558 Remington et al. Mar. 9, 1954 7 2,683,271 Taylor July 13, 1954 2,747,270 Crawford May 29, 1956 2,811,058 Fletcher et al Oct. 29, 1957 2,858,017 Kent et al. Oct. 28, 1958 2,896,782 Billen et al July 28, 1959 

1. A TOOL CARRIER FOR A FLOW-DEFORMATION PRESS, COMPRISING IN COMBINATION, A CARRIER MEMBER PIVOTABLE BETWEEN TWO WORKING POSITIONS ABOUT AN AXIS SUBSTANTIALLY PERPENDICULAR TO THE PLANE OF SAID MEMBER, THE LATTER BEING ADAPTED TO HOLD A PAIR OF INTERCHANGEABLE PRESS TOOLS AT LOCATIONS RADIALLY SPACED APART FROM SAID AXIS, SAID TOOLS ALTERNATELY FACING ANOTHER PRESS TOOL IN ONE OF SAID WORKING POSITIONS, ADJUSTABLE LIMIT STOPS LOCATED AT BOTH ENDS OF THE PIVOTAL MOVEMENT, AND MEANS FOR PIVOTING SAID CARRIER MEMBER SO AS ALTERNATELY TO BRING EACH OF SAID TOOLS OPPOSITE SAID ANOTHER TOOL WHILE THE OTHER TOOL IS PIVOTED AWAY THEREFROM, SAID PIVOTING MEANS INCLUDING A POSITIVELY ACTUATED CRANK MEMBER PERFORMING AN ANGULAR MOVEMENT LARGER THAN SAID PIVOTAL MOVEMENT OF THE CARRIER MEMBER, AND A TORSION BAR CONNECTING SAID MEMBERS SUBSTANTIALLY ALONG SAID AXIS, SAID TORSION BAR BEING ADAPTED FOR URGING ALTERNATE ENGAGING SURFACES OF SAID CARRIER MEMBER INTO, AND MAINTAINING THEM IN CONTACT WITH RESPECTIVE ONES OF SAID LIMIT STOPS. 